This invention relates to an image recording apparatus which applies a plurality of light beams different in wavelength to a photo-sensitive material to record an image thereon.
One example of an apparatus in which a density signal representing an image is converted into an optical signal, and the optical signal is applied to a photo-sensitive material to record the image thereon is a color image recording apparatus in which at least three (red, green and blue) gas lasers or semiconductor lasers are used for optical exposure.
In one example of an image recording apparatus of this type, in order to apply three light beams having desired intensity substantially to one and the same point on the color photo-sensitive material, three light beams are emitted in parallel, and the optical axes of the light beam thus emitted are aligned with one another with half-mirrors or dichroic mirrors in the optical exposure operation. However, the apparatus is disadvantageous in that the number of components in the optical system is relatively large, and delicate adjustment is required for completely aligning the optical axes of the three light beams with one another, thus taking a relatively long period of time.
On the other hand, a method may be employed in which the three light beams in parallel are applied to the photo-sensitive material by scanning, as they are, and the shifts in irradiation of the three light beams are measured during the manufacture of the apparatus, so that the light emission timing is adjusted according to the shifts in irradiation of the light beams thus measured. In the timing adjustment, for instance the three light beams' image-formed positions are subjected to photoelectric conversion by means of a microscope and a television camera to obtain image signals, from which the shifts of the light beams' image-formed positions are measured. The shifts thus measured are stored in non-volatile storage in the image recording apparatus, so that the light emission timing is thereafter controlled in the optical exposure operation. Accordingly, it is necessary to provided a relatively intricate device for the image-formed position adjustment. And the provision of such a device does not work for the shifts of the light beams' image formed positions which occur accidently or with the lapse of time.